IOCatalogue in IOKitUser in Apple iOS before 7 allows attackers to cause a denial of service (NULL pointer dereference and device crash) via a crafted application.
http://www.securitytracker.com/id/1029054
http://support.apple.com/kb/HT5934
http://lists.apple.com/archives/security-announce/2013/Sep/msg00006.html
http://lists.apple.com/archives/security-announce/2013/Oct/msg00004.html